The present invention relates to an apparatus for attaching to bone. More particularly, the present invention is directed to a bone screw and includes an associated screwdriver for driving the screw into bone.
Various types of fasteners are known for use in the medical field for attachment to human bone matter. Most of the known fasteners, whether permanent or temporary, are made of a bio-compatible metal, such as titanium or a titanium alloy, or a bio-absorbable material. Many of the commonly used fasteners are self-tapping or self-drilling bone screws. Self-tapping and/or self-drilling bone screws are often used in conjunction with a bio-compatible metal plate, such as in oral or maxillofacial surgery.
Of particular concern in the medical field is the ability of a bone screw to be retained on the end of an associated screwdriver during placement of the screw on the proper location of the bone. This concern arises because frequently the surgeon can only use one hand to pick-up the bone screw and place it in the proper attachment location, and because the relatively small size of such bone screws can make them difficult to work with.
Another concern for bone screws is the ability of the screwdriver to remain engaged with the screw while the screw is being driven into the bone. This concern arises because disengagement of the screwdriver from the screw could result in loss of the screw, or in harmful contact of the screwdriver with adjacent body tissue.
Accordingly, an apparatus for attaching to bone which retains a bone screw on the end of an associated screwdriver during pick-up and placement of the screw, as well as during driving of the screw, is desirable.
The present invention is an apparatus for attaching to bone. The apparatus comprises a one-piece, homogeneous screw engageable by a driver for driving the screw into bone. The screw has a shaft portion and a head portion extending from the shaft portion. The shaft portion has an outer surface with a thread convolution. The head portion includes oppositely disposed first and second axial ends and a peripheral surface extending between the ends. The first axial end adjoins the shaft portion. The second axial end includes an end surface. The head portion has a plurality of slots extending axially from the end surface to the first axial end. The slots further extend through the peripheral surface of the head portion and radially inward from the peripheral surface of the head portion.
In accordance with another aspect of the present invention, the apparatus further comprises a driver for driving the screw into bone. The driver has an end section with a plurality of blades projecting axially from the end section. Each of the plurality of blades is adapted for receipt in and to drivingly engage a respective one of the slots in the head portion of the screw. Further, each blade has a peripheral surface that corresponds to the shape of the peripheral surface on the head portion of the bone screw.